```
// luogu-judger-enable-o2
#include<bits/stdc++.h>
using namespace std;
struct point{
int x,y;
point(int xx,int yy){
x=xx;
y=yy;
}
};
int a[32][32];
int book[32][32],don[4][2]={{-1,0},{1,0},{0,-1},{0,1}},n;
int i,j,k,tx,ty;
queue<point> q;
void bfs(){
while(!q.empty()){
point p=q.front();
q.pop();
for(k=0;k<4;k++){
tx=p.x+don[k][0];
ty=p.y+don[k][1];
if(tx<0||tx>=n+2||ty<0||ty>=n+2)
continue;
if(a[tx][ty]==0&&book[tx][ty]==0){
a[tx][ty]=2;
book[tx][ty]=1;
point point1(tx,ty);
q.push(point1);
}
}
}
}
int main()
{
cin>>n;
for(i=1;i<=n;i++)
for(j=1;j<=n;j++){
cin>>a[i][j];
}
q.push(point(0,0));
book[0][0]=1;
bfs();
for(i=1;i<=n;i++){
for(j=1;j<=n;j++){
cout<<2-a[i][j]<<' ';
}
cout<<endl;
}
return 0;
}
```
by 听取MLE声一片 @ 2020-01-31 18:00:43
@[听取mc声一片](/user/253738) 边界是在n*n的方格里呀，没发现啥错呀
by 青苹果 @ 2020-01-31 18:03:35
@[青苹果](/user/118279) 您的遍历好像没有标记
by 听取MLE声一片 @ 2020-01-31 18:06:13
…
by 听取MLE声一片 @ 2020-01-31 18:06:37
@[听取mc声一片](/user/253738) 你结构体里面还套了函数，我看不太懂。。。
by 青苹果 @ 2020-01-31 18:08:55
我还是去写动规吧…
by 听取MLE声一片 @ 2020-01-31 18:09:12
```cpp
void bfs(int x,int y)
{
b[x][y]=5;
struct student c;
c.a=x;
c.b=y;
q.push(c);
while(!q.empty())
{
c=q.front();
q.pop();
int xx=c.a;
int yy=c.b;
for(int i=0;i<=3;i++)
{
//cout<<"aaaaaa"<<endl;
int t=xx+d[i][0];
int s=yy+d[i][1];
if(t>=1&&t<=n&&s>=1&&s<=n&&map[t][s]==0)
{
////////// map[t][s]=1;
b[t][s]=5;
c.a=t;
c.b=s;
q.push(c);
}
}
}
```
by 听取MLE声一片 @ 2020-01-31 18:12:01
```cpp
#include <iostream>
#include <cstring>
#include <cstdio>
#include <queue>
using namespace std;
int n,map[35][35],b[35][35];
queue<struct student>q;
struct student{
int a,b;
};
int d[][2]={{-1,0},{0,1},{1,0},{0,-1}};
void bfs(int x,int y)
{
b[x][y]=5;
struct student c;
c.a=x;
c.b=y;
q.push(c);
while(!q.empty())
{
c=q.front();
q.pop();
int xx=c.a;
int yy=c.b;
for(int i=0;i<=3;i++)
{
//cout<<"aaaaaa"<<endl;
int t=xx+d[i][0];
int s=yy+d[i][1];
if(t>=1&&t<=n&&s>=1&&s<=n&&map[t][s]==0)
{
map[t][s]=1;
b[t][s]=5;
c.a=t;
c.b=s;
q.push(c);
}
}
}
}
int main()
{
int i,j;
cin>>n;
for(i=1;i<=n;i++)
for(j=1;j<=n;j++)
cin>>map[i][j];
for(i=1;i<=n;i++)//第1,n行
{
if(map[1][i]==0)
bfs(1,i);
if(map[n][i]==0)
bfs(n,i);
}
for(i=1;i<=n;i++)//第1,n列
{
if(map[i][1]==0)
bfs(i,1);
if(map[i][n]==0)
bfs(i,n);
}
for(i=1;i<=n;i++)
{
for(j=1;j<=n;j++)
{
if(b[i][j]==5)
cout<<"0"<<" ";
else if(map[i][j]==1)
cout<<"1"<<" ";
else if(map[i][j]==0)
cout<<"2"<<" ";
}
cout<<endl;
}
return 0;
}
```
by 听取MLE声一片 @ 2020-01-31 18:14:18
你再试试这一个
by 听取MLE声一片 @ 2020-01-31 18:15:12
@[青苹果](/user/118279)
by 听取MLE声一片 @ 2020-01-31 18:15:17